The present invention relates to a method and a device for assistance with the piloting of an aircraft, especially of a transport airplane.
From the patent FR-2 689 231, a method is known for assistance with piloting, according to which an information presentation which represents at least one vertical plane along a flight plan of said aircraft is presented on at least one visual-display screen of an aircraft, and which includes:
an axis system, in which a y-axis is graduated in altitude, and an x-axis is graduated in distance from the position of the aircraft;
a particular symbol representing the aircraft, which is arranged on said y-axis at a position representative of the altitude of said aircraft; and
a plot representing a datum trajectory which the aircraft has to follow in said vertical plane.
Said plot is formed from a plurality of straight-line segments joining waypoints together. Moreover, at said waypoints, altitude-constraint symbols are provided, which indicate a maximum altitude and/or a minimum altitude which the aircraft has to comply with when it arrives at said waypoints.
However, these altitude-constraint symbols, which are formed by small triangles, do not present the real situation in a meaningful and easily readable way. Moreover, such a presentation may be a source of errors. For example, if a datum altitude varies greatly a little upstream (or downstream) of a waypoint, a pilot of the aircraft can be induced into error by thinking that the datum altitude which is visually displayed at said waypoint is also confirmed upstream (or downstream) of it.
Moreover, from the patent FR-2 744 525, there is known an assistance method of the same type as that quoted above. However, according to this known method, the x-axis is not graduated in distance, but in time, and the time axis is scrolled so as to maintain, at a fixed position on the visual-display screen, an x-coordinate representing the time at the instant of the display.
The present invention relates to a method for assistance with the piloting of an aircraft, making it possible to remedy the abovementioned drawbacks.
To that end, said method, according to which a first information presentation which represents at least one. vertical plane along a theoretical flight trajectory of said aircraft is presented on at least one visual-display screen of said aircraft, and which includes:
an axis system, in which a y-axis is graduated in altitude, and an x-axis is graduated in distance from the position of the aircraft;
a particular symbol representing the aircraft, which is arranged on said y-axis at a position representative of the altitude of said aircraft; and
a first plot representing a theoretical flight trajectory of said aircraft in said vertical plane, is noteworthy, according to the invention, in that said first information presentation further includes:
at least one second plot corresponding to a safety altitude; and
a third plot corresponding to a contour of the terrain in said vertical plane.
Thus, by virtue of the invention, the pilot is provided with an easily comprehensible and readable presentation of the vertical situation (position and trajectory) of the aircraft, with respect to synthetic obstacles (safety altitude) and real obstacles (terrain), and this is done throughout the flight (even if, at a given instant, the entire flight path remaining to be traveled may not be visible on the screen, for reasons of space available on said screen). It is thus possible to adapt the trajectory of the aircraft to these various obstacles, and to do so well upstream of a potential problem area. This obviously makes it possible to increase the safety of the flight.
Moreover, by virtue of the invention, the abovementioned important information (theoretical flight trajectory, safety altitude, contour of the terrain) is represented by way of the same type of graphics (namely a plot), which facilitates reading them and simplifies the monitoring of the situation of the aircraft.
It is known that different types of safety altitude are available, on the basis of the sources of information which define these altitudes, certain sources, especially those for which analysis is limited to reduced areas, being more appropriate than others.
Advantageously, said first information presentation further includes a fourth plot corresponding to a vertical section of a weather image originating from a radar.
In the context of the present invention, the various plots can be considered not only in a vertical plane (zero xe2x80x9cthicknessxe2x80x9d), but also in a vertical strip of thickness adapted to the navigation accuracy required [for example RNP (Required Navigation Performance)].
According to the invention, in order to improve the presentation of the safety altitude, the safety-altitude values used to form said second plot originate from at least two different information sources, and the values from one or from the other of said information sources are used, depending on the phase of flight of the aircraft and of the trajectory followed.
For preference:
when the aircraft finds itself outside a predefined route, the safety-altitude values used for all the phases of flight originate from an information source defining sector-based safety altitudes over quadrangular sectors, preferably of the MORA (Minimum Off Route Altitude) type, except for the approach phase, for which the safety-altitude values used are those originating from an information source defining sector-based safety altitudes over circular sectors, preferably of the MSA (Minimum Safe Altitude) type; and/or
when the aircraft finds itself on a predefined route, the safety-altitude values used are those originating from an information source defining the route safety altitudes.
Furthermore, advantageously, if said second plot goes outside said first information presentation by reason of the scale chosen for the y-axis, the numerical value of the safety altitude is indicated on said first information presentation.
Moreover, in order to improve the abovementioned monitoring of the situation of the aircraft with respect to the various obstacles (synthetic and real), advantageously:
a first warning symbol is presented on said first information presentation when the theoretical trajectory of the aircraft, with respect to said second plot (safety altitude), is not in accordance with predefined stipulations, for example when it is too close to a safety altitude or passes (downward) through such a safety altitude; and/or
a second warning symbol is presented on said first information presentation when the theoretical trajectory of the aircraft, with respect to said third plot (contour of the terrain), is not in accordance with predefined stipulations, in particular when it is too close to the terrain.
In the context of the present invention, the contour of the terrain can be represented by different types of plots, such as inclined segments or smoothed curves, for example. However, for preference, the terrain is represented, on said first information presentation, by a series of adjacent rectangles making it possible to form said third plot.
In one preferred embodiment, said visual-display screen, preferably an ND (Navigation Display) navigation screen, includes at least two visual-display windows, of which a first window comprises said first information presentation and a second window comprises a second information presentation which, among other things, includes a plot representing a theoretical flight trajectory of the aircraft in a horizontal plane.
Advantageously, the scale of the x-axis and, for at least some scale values, the scale of the y-axis of said first information presentation depend on the scale of said second information presentation. For preference, these axis scales are proportional to the scale of said second information presentation.
The present invention also relates to a device for assistance with the piloting of an aircraft, of the type including at least:
a plurality of information sources;
an information acquisition and processing unit, which is linked to said information sources; and
display means linked to said information acquisition and processing unit and presenting, on at least one visual-display screen, a first information presentation which represents at least one vertical plane along a theoretical flight trajectory of said aircraft and which includes:
an axis system, in which a y-axis is graduated in altitude, and an x-axis is graduated in distance from the position of the aircraft;
a particular symbol representing the aircraft, which is arranged on said y-axis at a position representative of the altitude of said aircraft; and
a first plot representing a theoretical flight trajectory of said aircraft in said vertical plane.
According to the invention, said assistance device is noteworthy in that said display means are formed in such a way as to present, moreover, on said visual-display screen, at the level of said first information presentation:
at least one second plot corresponding to a safety altitude; and
a third plot corresponding to a contour of the terrain in said vertical plane.
Advantageously, said assistance device further includes means capable of being actuated by an operator and allowing the latter to amend information taken into account by the information acquisition and processing unit.